HI thanks I added in your suggested extra resolutions for 1920x1080... They show up but they're all out of range. The highest one that shows a test pattern is 1920x1080@60 despite it showing in ScreenMode preferences as @61...Raziel wrote:Judging from your tries something seema to calculate the frequencies wrong.
wrt the wrong freuqency displayed: Yes, as i said in a previous post, ScreenModePrefs is bugged in more than one way...1920x1080@61 with H freq 68.70 kHz = Displays test pattern (weirdly this on is actually @60 in my icon information but shows as @61 in ScreenModes)
1920x1080@65 with H freq 72.88 kHz = the dreaded "Out of Range"
But ultimately (for now) that means that your monitor can only handle Horizontal frequencies upto around ~70 KHz
You should definitely try some more resolutions to pinpoint the exact HFreq where it breaks.See which one is the highest setting you can use and what HFreq it displays (I bet @62 is the one).
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1920x1080@62 1920x1080@63 1920x1080@64
Your problem here is, that some component does a wrong frequency calculation (judging from your successful tries on Linux), be it the gfx driver or the underlying P96 gfx system, i don't know.
I also think the frequency calculation is only off by a small number, maybe even just some kind of rounding error or similar (see the wrong Frequency display in ScreenModePrefs), but it's enough to make you lose a perfectly fine resolution (due to the small number error cumulating with bigger frequency calculation).
Take a look here to calculate (roughly) the VFreq that is needed to display a frequency.
So, let's speculate from your tries that your monitor (for whatever reason on the AmigaOS4 system) is limited to a maximum of approx. 70 kHz.
1440 x 1,05 x 50 would be 75600 Hz (Vertical frequency) which will always be beyond of what your monitor can handle (not really, but on the AmigaOS4 system).
Calculating that backwards (70000 / 1.05 / 1440) would mean you "could" display that resolution *if* your monitor could handle @45 or @46 Hz, which it obviously can't. (With an exact figure you can do a more precise calculation, but i fear it will always be lower than 50 Hz (which your tries already showed, as it didn't work with @50).
There's a bug somewhere and i tend to point the finger at the P96 subsystem.
But of course, you can always write to Hans (gfx driver maintainer) and point him to this thread.
He could probably right some of my wrongs...or stomp this whole discussion into the dust and come up with the clever solution we haven't thought of
I'll contact Hans and see if he can help at all. Thanks so much for trying to get this working for me. It does seem like a bug as you say...